The oil sands in Northern Alberta are one of the largest hydrocarbon deposits in the world. The oil sands are bitumen mixed with water and sand, of which 75-80% is inorganic material (sand, clay and minerals), 3-5% water with bitumen content ranging from 10-18%. Each oil sand grain has three layers: an envelope of water surrounds the grain of sand and a film of bitumen surrounds the water. Located in north eastern Alberta, the oil sands are exploited by both open pit mining and in situ methodologies. The open pit mining uses a shovel/truck combination for bitumen deposits that are close to the surface. The in situ methods use cycle steam simulation and steam assisted gravity drainage for bitumen deposits that are too deep for economical mining. The present practice of bitumen extraction from the mined oil sands uses large amounts of hot water and caustic soda to form a oil sands ore-water slurry, this slurry is processed to separate it into three streams; bitumen, water and solids. The water consumed in this process is high, at a ratio of 9 barrels of water per 1 barrel of oil. The bitumen recovered by the current extraction methods of open pit mining is about 91% by weight, the balance of the bitumen remains in both; solids and water streams, making these toxic and with a need for containment. The tailings ponds created in Northern Alberta from oil sands operations are vast and considered by many an ecological disaster. More recently, major breakthroughs in extracting bitumen from oil sands are claimed by oil sands operators, these reduce the temperature of the water from 80 C to 60 C while maintaining and even improving bitumen recovery rates, resulting in a 75% energy savings to heat the water.
The extracted bitumen from the oil sands contain wide boiling range materials from naphthas to kerosene, gas oil, pitch, etc., and which contain a large portion of material boiling above 524 C. This bitumen contains nitrogenous and sulphurous compounds in large quantities. Moreover, they contain organo-metallic contaminants which are detrimental to catalytic processes, nickel and vanadium being the most common. A typical Athabasca bitumen may contain 51.5 wt % material boiling above 524 C, 4.48 wt % sulphur, 0.43 wt % nitrogen, 213 ppm vanadium and 67 ppm nickel. Technologies for upgrading bitumen into lighter fractions can be divided into two types of processes: carbon rejection processes and hydrogen addition processes. Both of these processes employ high temperatures to crack the long chains. In the carbon rejection process, the bitumen is converted to lighter oils and coke. Examples of coking processes are fluid bed cokers and delayed bed cokers, they typically remove more than 20% of the material as coke, this represents an excessive waste of resources. In hydrogen addition processes, and in the presence of catalysts an external source of hydrogen (typically generated from natural gas) is added to increase the hydrogen to carbon ratio, to reduce sulphur and nitrogen content and prevent the formation of coke. Examples of hydrogen addition processes include: catalytic hydroconversion using HDS catalysts; fixed bed catalytic hydroconversion; ebullated catalytic bed hydroconversion and thermal slurry hydroconversion. These processes differ from each from: operating conditions, liquid yields, catalysts compositions, reactor designs, heat transfer, mass transfer, etc., the objective being to decrease the molecular weight of large fractions to produce lighter fractions and remove sulphur and nitrogen. A process for thermal and catalytic rearrangement of shale oils is described by Eakman et al. in U.S. Pat. No. 4,459,201. The disclosed process uses two vessels, a reactor and a combustor where the sand is circulated as the heating medium. A method to process oil sands described by Gifford et al. in U.S. Pat. No. 4,094,767, describes a process to produce hot coked sand and oil. Another process for direct coking of oil sands was described by Owen et al. in U.S. Pat. No. 4,561,966, where the oil sands are introduced into a fluid coking vessel which has at least two coking zones. This process receives its heat source from a circulating stream of hot sand between the combustor and the fluid coking vessel. A thermal process described by Taciuk in U.S. Pat. No. 4,306,961, described a process to recover and upgrade bitumen from oil sands in a rotating kiln processor. A process of an indirectly heated thermochemical reactor processes is described by Mansour et al. in U.S. Pat. No. 5,536,488, where the use of pulse enhanced combustors immersed in a fluidized bed are employed. The described process promotes the use of catalysts for steam reforming and production of syngas.